การออกแบบและพัฒนาซอฟต์แวร์ บทที่ 7 การทดสอบโปรแกรม ปริญญา น้อยดอนไพร สาขาวิชาวิทยาการคอมพิวเตอร์ คณะวิทยาศาสตร์และเทคโนโลยี มหาวิทยาลัยราชภัฏสุราษฎร์ธานี

การทดสอบโปรแกรม กระบวนการในการทดสอบ กระบวนการในการหาข้อผิดพลาดของโปรแกรม กลยุทธ์การทดสอบ เครื่องมือช่วยในการทดสอบ แบบต่าง ๆ ของการทดสอบ

Testing phases

The defect testing process

Black-box testing

Equivalence partitioning

Equivalence partitioning Partition system inputs and outputs into ‘equivalence sets’ If input is a 5-digit integer between 10,000 and 99,999, equivalence partitions are <10,000, 10,000-99, 999 and > 10, 000 Choose test cases at the boundary of these sets 00000, 09999, 10000, 99999, 10001

Equivalence partitions

White-box testing

Path testing The objective of path testing is to ensure that the set of test cases is such that each path through the program is executed at least once The starting point for path testing is a program flow graph that shows nodes representing program decisions and arcs representing the flow of control Statements with conditions are therefore nodes in the flow graph

Program flow graphs Describes the program control flow. Each branch is shown as a separate path and loops are shown by arrows looping back to the loop condition node Used as a basis for computing the cyclomatic complexity Cyclomatic complexity = Number of edges - Number of nodes +2

Cyclomatic complexity The number of tests to test all control statements equals the cyclomatic complexity Cyclomatic complexity equals number of conditions in a program Useful if used with care. Does not imply adequacy of testing. Although all paths are executed, all combinations of paths are not executed

Binary search flow graph

Independent paths 1, 2, 3, 8, 9 1, 2, 3, 4, 6, 7, 2 1, 2, 3, 4, 5, 7, 2 1, 2, 3, 4, 6, 7, 2, 8, 9 Test cases should be derived so that all of these paths are executed A dynamic program analyser may be used to check that paths have been executed

Integration testing Tests complete systems or subsystems composed of integrated components Integration testing should be black-box testing with tests derived from the specification Main difficulty is localising errors Incremental integration testing reduces this problem

Incremental integration testing

Approaches to integration testing Top-down testing Start with high-level system and integrate from the top-down replacing individual components by stubs where appropriate Bottom-up testing Integrate individual components in levels until the complete system is created In practice, most integration involves a combination of these strategies

Top-down testing

Bottom-up testing

Tetsing approaches Architectural validation System demonstration Top-down integration testing is better at discovering errors in the system architecture System demonstration Top-down integration testing allows a limited demonstration at an early stage in the development Test implementation Often easier with bottom-up integration testing Test observation Problems with both approaches. Extra code may be required to observe tests

Interface testing Takes place when modules or sub-systems are integrated to create larger systems Objectives are to detect faults due to interface errors or invalid assumptions about interfaces Particularly important for object-oriented development as objects are defined by their interfaces

Interface testing

Interfaces types Parameter interfaces Shared memory interfaces Data passed from one procedure to another Shared memory interfaces Block of memory is shared between procedures Procedural interfaces Sub-system encapsulates a set of procedures to be called by other sub-systems Message passing interfaces Sub-systems request services from other sub-systems

Interface errors Interface misuse Interface misunderstanding A calling component calls another component and makes an error in its use of its interface e.g. parameters in the wrong order Interface misunderstanding A calling component embeds assumptions about the behaviour of the called component which are incorrect Timing errors The called and the calling component operate at different speeds and out-of-date information is accessed

Interface testing guidelines Design tests so that parameters to a called procedure are at the extreme ends of their ranges Always test pointer parameters with null pointers Design tests which cause the component to fail Use stress testing in message passing systems In shared memory systems, vary the order in which components are activated

Stress testing Exercises the system beyond its maximum design load. Stressing the system often causes defects to come to light Stressing the system test failure behaviour.. Systems should not fail catastrophically. Stress testing checks for unacceptable loss of service or data Particularly relevant to distributed systems which can exhibit severe degradation as a network becomes overloaded

A testing workbench

เครื่องมือช่วยในการทดสอบ เครื่องมือสร้างกรณีทดสอบ เครื่องมือทดสอบการ Coverage เครื่องมือการประมวลผลการทดสอบ เครื่องมือจัดการกับกรณีทดสอบ

แบบต่าง ๆ ของการทดสอบ Unit Test Integration Test Functional Test (Features Test, Acceptance Test) Stress Test Performance Test Qualification Test Loading Test Compatibility Test Installation Test Regression Test